• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Relay Coil Ignition Circuit | P0691, P0693 | P0480, P0481 | -- | -- |
Relay Switch Ignition Circuit | * | * | -- | -- |
Fan Relay 1 Control Circuit | P0691 | P0480 | P0692 | -- |
Fan Relay 2 Control Circuit | P0693 | P0481 | P0694 | -- |
Relay Fan Supply Voltage Circuit | * | * | ** | -- |
* Fans inoperative without a DTC. ** Fans always ON without a DTC. |
The Cooling Fan Relay 1 or the Fan Low Relay, and the Cooling Fan 2 or the Fan Hi Relay are controlled by the powertrain control module (PCM). Battery voltage is supplied to the cooling fan relay coil. The PCM monitors the voltage on the control circuit of the relay. When the relay is OFF, the voltage should be near battery voltage on the control circuit of the relay. When the relay is commanded ON, the voltage will be low on the control circuit of the relay. The PCM will provide ground on the control circuit of the relay using a low side driver.
• | The ignition is ON or the engine is running. |
• | The ignition voltage is between 8 and 18 volts. |
• | The engine speed is more than 40 RPM. |
• | DTCs P0480, P0481, P0691, P0692, P0693 and P0694 run continuously once the above conditions are met. |
The PCM detects an open circuit on the cooling fan 1 relay control circuit.
The PCM detects an open circuit on the cooling fan 2 relay control circuit.
The PCM detects a short to ground on the cooling fan 1 relay control circuit.
The PCM detects a short to voltage on the cooling fan 1 relay control circuit.
The PCM detects a short to ground on the cooling fan 2 relay control circuit.
The PCM detects a short to voltage on the cooling fan 2 relay control circuit.
The PCM detects a short to voltage, a short to ground, or an open/high resistance on the cooling fan relay control circuits.
• | DTCs P0480 and P0481 are Type B DTCs. |
• | DTCs P0691, P0692, P0693 and P0694 are Type C DTCs. |
• | DTCs P0480 and P0481 are Type B DTCs. |
• | DTCs P0691, P0692, P0693 and P0694 are Type C DTCs. |
The following two tables illustrate the COOLING FAN 1 relay and the COOLING FAN 2 relay terminal locations in the underhood fuse block. The third table illustrates the COOLING FAN 3 relay terminal locations in the relay electrical connector.
Terminal Identification | |
---|---|
Cooling Fan Supply Voltage | B+ Coil |
Control | B+ Switch |
Front of Vehicle |
Terminal Identification | |
---|---|
Cooling Fan Supply Voltage | B+ Coil |
Control | B+ Switch |
Front of Vehicle |
Terminal Identification | ||
---|---|---|
B+ Coil | Voltage to Right Cooling Fan | Ground |
Voltage from Left Cooling Fan | -- | Control |
Locking Tab |
Cooling System Connector End Views
Cooling System Description and Operation
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
⇒ | If the test lamp does not illuminate, test the relay coil ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the relay coil ignition circuit fuse is open, test all components connected to the relay coil ignition circuit and replace as necessary. |
⇒ | If the test lamp is always ON, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the PCM. |
⇒ | If the test lamp is always OFF, test the relay coil control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the PCM. |
⇒ | If the resistance is not within the specified range, replace the relay. |
• | 30 and 86 |
• | 30 and 87 |
• | 30 and 85 |
• | 85 and 87 |
⇒ | If not the specified value, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
⇒ | If greater than the specified range, replace the relay. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for PCM replacement, setup, and programming |